Computer Science Homework Help

Respond to peer discussions (please references should be in APA style). Thanks.

Peer 1: For data encryption, authentication, and digital signatures, cryptographic algorithms are often used, but they must be bound to a machine or a user identity to be then applied. The public key infrastructure (PKI) system is used to bridge identity information (email addresses, DNS names, etc.) with the cryptographic keys required for authentication or encryption.

RSA (Asymmetric Encryption Algorithm)

This symmetric encryption algorithm, also known as RSA, was developed by Ron Rivest, Adi Shamir, and Leonard Adleman (RSA) in 1977. A key aspect of its potency stems from its use of “prime factorization.” The method consists of multiplying two huge random prime numbers to create a third huge number. The difficult part of this problem is finding the original prime numbers from an overlarge multiplied number.

Using the right key length and enough entropy to generate the puzzle, it turns out to be virtually impossible for even today’s supercomputers to solve, let alone humans. In 2010, a team of researchers cracked the RSA-768 bit key, which has a much smaller size than the current standard 2048-bit RSA key. This took them over 1,500 years to crack (distributed over hundreds of computers).

Scalability is one of RSA’s greatest advantages. You can choose from 768-bit encryption keys, 1024-bit encryption keys, 2048-bit encryption keys, 4096-bit encryption keys, etc. The difficulty of brute forcing lower-key lengths increases with increasing key length, so even if you brute force the lower key lengths, you can still use encryption with the higher key lengths.

It is also straightforward to implement it in the public key infrastructure (PKI) because it employs a simple mathematical approach. Asymmetric encryption algorithms like RSA are the most widely used due to their ability to adapt to PKI-encrypted data. Crypto currency, SSL/TLS certificates, and email encryption are just a few of the applications in which RSA is widely used.

In real time, this is used in the banking systems. Many banks accept many requests for transactions from its customers over an insecure network. Bank will use a public-private key for its customer’s encryption and then decrypt the data sent from customers and a private key is used for the decryption while the public key is used for encryption since RSA uses both public and private key.

In summary, cryptography has become easily accessible to even the average computer user, allowing them to protect their digital files on a local or remote storage system, as well as allowing them to communicate securely. In spite of its wide availability, cryptography is often not used when it should or is implemented or used in a way that is insecure or ineffective.

By using cryptography to certify communications and authentication with an Internet service that is hopelessly outdated in security patches or harboring spyware, cryptography is often used ineffectively.

Reference:

https://www.cryptomathic.com/news-events/blog/summary-of-cryptographic-algorithms-according-to-nist

https://www.globalsign.com/en/blog/glossary-of-cryptographic-algorithms

D. Stinson, Cryptography: Theory and Practice, CRC Press, 3rd Ed., 2005. Solid introduction, but only for the mathematically inclined. A.J. Menezes, P.C. van Oorschot, S.A. Vanstone, 

Peer 2:

Message Digest Algorithm 5 (MD5) refers to a one-way cryptographic hash function algorithm that is well known for producing a 128-bit hash value meant to render brute-forcing as computationally infeasible due to the difficulty of producing two messages with the same message digest (Shacklett, 2017). In this case, the message digest refers to the hashed output. This hash function was used mostly in contexts where the integrity of a file needs to be determined as a checksum, but in recent years the algorithm has been deemed as insufficient for optimal security. 

MD5, created in 1991, aimed to determine the safety and validity of files through website downloads. For example, MD5 uses checksums which means downloaded files are checked against their unique hash to determine if the original file has been tampered with. However, the algorithm is now considered cryptographically broken due to hackers being able to create files with the same hash, which renders the algorithm’s ability to check for tampering moot (“What is MD5 and why is it considered insecure?”, 2020). In spite of the debate regarding MD5’s validity, roughly 25% of major content management systems still use MD5 as a means of storing user passwords and using password hashing to obscure the original input (Cimpanu, 2019). 

Implementing MD5 consists of five steps: append padding bits, append length, initialize MD buffer for computing the message digest after hash creation, process message in 16-word bits, and output so the text is now hashed. Ronald Rivest, designer of the MD5 algorithm, defines word as a 32-bit quantity and byte as an eight-bit quantity. He summarizes the purpose of the algorithm as being intended “…for a digital signature application, where a large file must be “compressed” in a secure manner before being encrypted with a private (secret) key under a public-key cryptosystem such as RSA” (Rivest, 1992).

Even though MD5 has been cautioned as an outdated cryptographic method, the algorithm is still utilized in companies with content management systems and has been a foundation for internet security for users. A possible direction that could be taken to strengthen the security of the MD5 algorithm is through the expansion of the length of the output that would make it more difficult to computationally get past (Bhandari et al., 2017). 

References

Bhandari, A., Bhuiyan, M., & Prasad, P. W. (2017). Enhancement of MD5 algorithm for secured web development. Journal of Software, 12(4), 240-252. https://doi.org/10.17706/jsw.12.4.240-252

Cimpanu, C. (2019, June 17). A quarter of major CMSs use outdated MD5 as the default password hashing scheme. ZDNet. https://www.zdnet.com/article/a-quarter-of-major-cmss-use-outdated-md5-as-the-default-password-hashing-scheme/

Rivest, R. (1992, April). The MD5 Message-Digest Algorithm. IETF | Internet Engineering Task Force. https://www.ietf.org/rfc/rfc1321.txt 

Peer 3:

I enjoyed reading your post as it provides some keys information about MAC. I learned that MAC is also one of the most secured Cryptographic Algorithms. The key to access the data is only shared between the sender and the receiver. This allows the message recipient to verify the integrity of the message and authenticate that the message’s sender has the shared secret key. If a sender does not know the private key, the hash value would then be different, which would tell the recipient that the message was not from the original sender. Most of the time, the information and the key code are sent in a separate notice; this is also another security level.  As stated on csrc.nist.gov, the message authentication code (MAC) “is generated from an associated message as a method for assuring the integrity of the message and the authenticity of the source of the message” (CSRC, n.d.). 

Reference

CSRC. (n.d.). Message authentication codes. Computer Security Resource Center | CSRC. https://csrc.nist.gov/projects/message-authentication-codes